Heat exchanger

Abstract

End rings are coupled with upper and lower ends of a cylindrical body tube. A plurality of first heat exchanger tubes are fitted and held in holes provided in a pair of first tube plates. A plurality of second heat exchanger tubes are fitted and held in holes provided in a pair of second tube plates. The inside of each first heat exchanger tubes forms a first-fluid passage for carrying a reformed gas. The space defined between an outer wall of each first heat exchanger tube and an inner wall of the corresponding second heat exchanger tube forms a second-fluid passage for carrying a coolant. The space defined among an inner wall of the body tube and outer walls of the second heat exchanger tubes form a third-fluid passage for carrying compressed air.

1. A heat exchanger for heat exchange among at least three fluids, comprising:
 a plurality of first heat exchanger tubes, each having a first-fluid passage formed therein to carry a first fluid; 
 a plurality of second heat exchanger tubes each formed to cover one of the first heat exchanger tubes corresponding thereto, each one of the second heat exchanger tubes defining a second-fluid passage formed to carry a second fluid between an inner wall of the one of the second heat exchanger tubes and an outer wall of the one of the first heat exchanger tubes; 
 a plurality of third heat exchanger tubes each formed to cover one of the second heat exchanger tubes corresponding thereto, each one of the third heat exchanger tubes defining a third-fluid passage formed to carry a third fluid between an inner wall of the one of the third heat exchanger tubes and an outer wall of the one of the second heat exchanger tubes; 
 a pair of first tube plates provided on first and second ends of the first heat exchanger tubes; 
 a pair of second tube plates provided on first and second ends of the second heat exchanger tubes; 
 a pair of third tube plates provided on first and second ends of the second heat exchanger tubes; 
 a first end ring extending between an outer edge of one of the first tube plates provided on the first ends of the first heat exchanger tubes and an outer edge of one of the second tube plates provided on the first ends of the second heat exchanger tubes, to define a second-fluid distribution chamber for distributing the second fluid into each second-fluid passage defined by each of the second heat exchanger tubes; 
 a second end ring extending between an outer edge of the other of the first tube plates provided on the second ends of the first heat exchanger tubes and an outer edge of the other of the second tube plates provided on the second ends of the second heat exchanger tubes, to define a second-fluid collection chamber for collecting the second fluid from each second-fluid passage defined by each of the second heat exchanger tubes; 
 a third end ring extending between an outer edge of one of the second tube plates provided on the first ends of the second heat exchanger tubes and an outer edge of one of the third tube plates provided on the first ends of the third heat exchanger tubes, to define a third-fluid distribution chamber for distributing the third fluid into each third-fluid passage defined by each of the third heat exchanger tubes; and 
 a fourth end ring extending between an outer edge of the other of the second tube plates provided on the second ends of the second heat exchanger tubes and an outer edge of the other of the third tube plates provided on the second ends of the third heat exchanger tubes, to define a third-fluid collection chamber for collecting the third fluid from each third-fluid passage defined by each of the third heat exchanger tubes. 
 
     
     
       2. A heat exchanger according to  claim 1 , wherein each one of the third heat exchanger tubes, one of the second heat exchanger tubes covered by the one of the third heat exchanger tubes, and one of the first heat exchanger tubes covered by the one of the second heat exchanger tubes are substantially coaxial with each other; and
 wherein the one of the third heat exchanger tubes encloses a midsection of the one of the second heat exchanger tubes, and the one of the second heat exchanger tubes encloses a midsection of the one of the first heat exchanger tubes. 
 
     
     
       3. A heat exchanger according to  claim 1 , further comprising a second-fluid introduction unit attached to the first end ring, to feed the second fluid into the second-fluid distribution chamber. 
     
     
       4. A heat exchanger according to  claim 1 , further comprising a second-fluid discharge unit attached to the second end ring, to discharge the second fluid from the second-fluid collection chamber. 
     
     
       5. A heat exchanger according to  claim 1 , further comprising a third-fluid introduction unit attached to the third end ring, to feed the third fluid into the third-fluid distribution chamber. 
     
     
       6. A heat exchanger according to  claim 1 , further comprising a second-fluid discharge unit attached to the fourth end ring, to discharge the third fluid from the third-fluid collection chamber. 
     
     
       7. A heat exchanger according to  claim 1 , wherein at least one fourth-fluid passage is formed to carry a fourth fluid around outer walls of the third heat exchanger tubes. 
     
     
       8. A heat exchanger according to  claim 1 , further comprising a body tube extending between the outer edges of the third tube plates, to define the fourth-fluid passage. 
     
     
       9. A heat exchanger according to  claim 8 , further comprising a fourth-fluid introduction unit attached to the body tube, to feed the fourth fluid into the fourth-fluid passage. 
     
     
       10. A heat exchanger according to  claim 8 , further comprising a fourth-fluid discharge unit attached to the body tube, to discharge the fourth-fluid from the fourth-fluid passage. 
     
     
       11. A heat exchanger according to  claim 8 , further comprising at least one baffle plate provided in the fourth-fluid passage.